DETERMINATION OF THE RISK AT WORKPLACE, ASSESSMENT AND ITS RANK CALCULATION, IN MINING ACTIVITIES

Volume 66 (2020), No. 1 http://gse.vsb.cz p. 69–75, ISSN 1802-5420 DOI 10.35180/gse-2020-0032 DETERMINATION OF THE RISK AT WORKPLACE, ASSESSMENT AND ITS RANK CALCULATION, IN MINING ACTIVITIES Kemajl ZEQIRI, Joze KORTNIK, Stojance MIJALKOVSKI Faculty of Geosciences, Department of Mining, Isa Boletini University, Mitrovice, Kosovo 2 Faculty of Natural Sciences and Engineering, Department of Geotechnology, Mining and Environment, University of Ljubljana, Ljubljana, Slovenia Faculty of Natural and Technical Sciences, Mining Engineering, Goce Delchev University, Shtip, R.N. Macedonia E-mail: kemajl.zeqiri@umib.net


INTRODUCTION
World consumption of minerals has increased to such an extent in modern times that more minerals were used in the 20th century than ever used throughout the previous centuries [4,5,6]. Practically, we are now a society that depends on automobiles, trains, telephones, television, computers, fertilizers, heavy machinery, industrial minerals for building construction, electricity production based on coal-fired power plants, nuclear plants. However, during all these times of mineral resources utilization, the mining industry and related activities have had extensive negative environmental impacts associated with natural disasters and human life loss. Unfortunately, the improvements to this are not satisfying to date [7].
In the mining industry more people are killed or injured than in any other industry worldwide. Over 15,000 miners are killed every year -and this is just the official number of deaths. There are most likely many more casualties.
Nevertheless, the society needs mining in order to meet their needs for mineral resources, and also mining has supported innovations, the economy and societal development [8,9]. On the other hand, facts and figures presented above related to mining disasters and accidents are disturbing. Despite the modern technologies and modern regulations on mine safety, the improvements during the mining activities have been insufficient. The legislation framework can never be fully comprehensive, and in line with certain mine specificities, the administrative reforms tend to be behind the technological progress [10,11].
The practice claims that the legislation on mining safety should be more flexible in terms of each mine's characteristics. Thus, mine safety management must ensure that all risks are identified, assessed and ranked properly to ensure long-term health and safety at the mine site [12,13,14].
However, risk determination, namely related to accidents, is a current challenge for many researchers due to the implications of many parameters and variables. Accident statistics, namely the consequences of accidents, have so far been the main parameters in the tendency for accident risk assessment and calculation. Nevertheless the accuracy of such a calculation depends directly on the mathematical equation but also on certain variables. For

GeoScience Engineering
Volume 66 (2020), No. 1 http://gse.vsb.cz p. 69-75, ISSN 1802-5420 DOI 10.35180/gse-2020-0032 example, some researchers show the risks calculation (risk score) as a multiple of occurrence and the impact of an occurrence (consequence), as it is shown in the formula below: Risk Score = Likelihood * Consequence [15] (1) Thus, such a calculation tends to be based on statistics or general parameters of the mine or a working unit, whereas the experience shows that risk management in mines should be based on specific cases. Based on the statements above, the main objective of this paper is to calculate the risk in the mining production based on a specific workplace.

MATERIALS AND METHODS
As mentioned above, there are several formulas and methodologies that have been used to calculate and assess the risk at work, but most of them use similar methodologies of general data on work accidents, such as the number of total accidents in a year, and serious injuries in a year. Some also include small injuries. The empirical Formula (Severity index) [11,15]

S = Number of serious injuries in a year
The above criterion is used to identify accident-prone mines. Fatal Accidents Serious Injures Small Injures 0 0 67 Considering the data on accidents in Tab.1, the calculation of Severity Index (S.I) will result in zero, which is non-sense with regard to KEK's Mines Safety Management. On the other hand, if we try to calculate the risk using Formula 3 below, consequently from Table 3, we get the risk percentage of 11.25 (A=11.25%). While the Severity index Formula (2) does not present the proper way to calculate the risk in KEK mines, Formula 3 lacks the parameters that would increase the reliability, such as workplaces of accident occurrence, cause/agent of accidents, etc. Therefore, considering these facts, and due to the reoccurrences of mines accidents caused by the same agents, it has encouraged us to use a methodology based on specific cases at a certain workplace. While the calculation is based on an empirical formula used for the assessment of the risk and its ranking, the categorisation of the risk potential is based on previous analyses of mines accidents at specific workplaces. We will use the parameter "P" as an accident occurrence parameter, with given nominal rates, from 0.90 to 7.90.
Nominal limits of parameter "P" are defined based on exposure time and under assumption of non-zero risk, as well as there is any risk with 100% chance. Below are given formulas:  Table 1 below gives the relation between the index of nominal rate of accident occurrence "P" and categorization of working-risk area. The working-risk area is provided based on historical accidents' statistics and it is the most important parameter in Formula 3 in order to estimate (rank) the risk of the working place.  Table 3.   Table 4, particularly rows 3, 5 and 7, shows the risk calculation based on time exposure at the workplace, and as can be seen, the risk rank is based on the time-exposure at the workplace (Formula 3, 4 and 5).  (3) consists of the quality of the statistics related to mining accidents, or the assessment of risk at the workplace. The types of accidents based on the consequences are listed in Table 2. However, the same calculation can be used if we setup the rate of risk by working places, as shown in Table 3. Table 6 below gives the risk calculation for the Slovenian Mining Industry, based on the statistical data for the period of 2007-2011.  Table 3, is calculated based on Formula 3, and based on statistics of the accidents at the Stan Terg mine, for the period 2007-2011 [18,19].

RESULTS AND DISCUSSION
The same methodology is used to calculate the risk in Table 5, based on accident statistics of Slovenian mines, and as can be seen the accident risk assessment (A) of less than 48%.
Nevertheless, it should be highlighted that there is a lack of available data related to accidents, such as the sites of accidents, cause/agent of accidents etc., which decreases the reliability of such calculations. Consequently, this leads to general conclusions on risk at certain mining operations, which will have negative impacts on future accident prevention measures.

Figure 1 Ratio of accidents based on workplaces at Stan Terg mine
As shown in Table 3, the highest risk of working places at the Stan Terg mines seems to be related to stope mining in ore extraction, and the main agent of the accidents is the "hit"see Fig.1. Thus, the nominal rate of accident in Tab.3. column A is from 1.90 to 6.90, or on average 4.4 (Tab.3, column C). Therefore, based on Table  2, for P = 4.4, the accident risk assessment (A) is above 60 % for the workplace 'stope-mining' in the Stan Terg mine.